A former parliamentary candidate has confirmed she is to take legal action over her deselection.
Sally Gimson said last month she was "delighted to have been selected" to represent Labour in Bassetlaw, Nottinghamshire.
But on Wednesday, Labour's National Executive Committee (NEC) axed her over "very serious allegations".
Lawyers for Ms Gimson are now seeking an injunction over this decision, calling the process "an utter sham".
Ms Gimson a former councillor in Camden, north London, was endorsed by the local party in Bassetlaw on 27 October.
The Local Democracy Reporting Service said it was understood the deselection came after complaints from the party in London, relating to "very serious allegations" concerning "protected characteristics" - this can relate to issues surrounding race, disability and sexuality.
The local party backed Ms Gimson at an emergency meeting on Wednesday night and appealed to Labour leader Jeremy Corbyn to "see sense".
Ms Gimson said: "I am baffled that when we have a party which talks about justice and fairness, and also talks about how local members need to be making decisions, that the central party can come in and say the decision made by local members here in Bassetlaw is not valid and they cannot endorse me."
Lawyers Mischon de Reya have written to the Governance and Legal Unit of the Labour Party.
In the letter they said: "The Labour Party has undertaken a process that is an utter sham conducted with no concern for the truth or fairness but with the single objective of ensuring our client does not run."
Former Bassetlaw MP John Mann, who has become a member of the House of Lords, called Ms Gimson's removal a "stitch-up".
The Labour Party earlier said it did not comment on its internal selection processes but has been approached for comment about the latest developments.
Currently the confirmed candidates for the seat are: Green Party, Kristopher Wragg; Brexit Party, Debbie Soloman and Liberal Democrat, Helen Tamblyn-Saville.
The Conservative Party are expected to choose their candidate shortly and Labour have until 14 November to make their final selection.